Serum phosphorylated α-synuclein: A potential biomarker of poststroke cognitive impairment

Abstract Background Ischemic stroke (IS) is characterized by cerebral infarction caused by acute cerebral vascular occlusion, with high rates of morbidity, mortality, and disability. Poststroke cognitive impairment, one of the major secondary impairments, is associated with greatly reduced quality of life in many patients with IS. Because poststroke cognitive impairment has insidious onset and progressive progression, the development of early warning biomarkers is essential for this disease. Methods In this study, we detected phosphorylated α-synuclein (p-α-syn) pathology in the brain of distal middle cerebral artery occlusion (dMCAO) mice and hypoxia mice. We collected blood samples and routine biochemistry data of patients with IS and those who underwent physical examination in Beijing Boai Hospital from July to December 2021. We examined the serum level of p-α-syn in those people by ELISA. Results The level of p-α-syn was significantly increased and showed pathological aggregation around the cerebral infarct in dMCAO mice. And the similar aggregation in neurons were also observed in the brain of chronic hypoxia mice, thus suggesting that hypoxia is the internal cause of α-syn pathology. The serum level of p-α-syn in patients with IS was significantly lower than that of control group, and this lower serum level was positively correlated with the cognitive level of these patients. Further association analysis revealed that the decrease in the serum high-density lipoprotein level of patients with stroke was significantly correlated with their decreased p-α-syn level. Conclusions Serum p-α-syn has the potential to serve as a biomarker for poststroke cognitive impairment.